(20 U.S.C. 6301 et. seq.), as amended by this Act, from programs. authorized under the Elementary and Secondary Education Act. of 1965 (20 U.S.C. 6301 et seq.), as in effect on the day before. the date of enactment of this Act.
The efficacy of a vaccine is different from its effectiveness. It is dependent on several factors such as: 1  adherence to vaccine schedules. 2  the disease â some diseases have vaccines against them that perform better than for other diseases. 3  the strain of vaccine â some vaccine strains are more effective than others.
Varicella vaccine, also known as chickenpox vaccine, is a vaccine that protects against chickenpox. One dose of vaccine prevents 95% of moderate disease and 100% of severe disease. Two doses of vaccine is more effective than one. If given to those who are not immune within five days of exposure to chickenpox it prevents most cases of disease. Vaccinating a large portion of the population also protects those who are not vaccinated.